Here is the dirty filter in question and the cleaning kit from AEM. The company's cleaning kit comes with enough cleaning solution and oil to treat your filter numerous times, so store it in a place where you can find it later.
We've shown you on numerous occasions how to install an aftermarket high-performance air filter and told you the reasons why - more air in, more power out, blah blah. This story will show you the proper way to clean your filter without damaging its filtering properties. Most of these filters, such as the AEM unit we're showing you, are constructed of a cotton-gauze material coated in super-secret oil. The cotton is used to act as a net, while the oil is what makes the tiny particles stick. One thing that makes these filters unique is the fact that they are washable and reuseable. But the use of industrial cleaners or improper cleaning methods can actually damage the fibers. With the proper cleaning, these filters will offer years of reliable service to your engine. So let's check it out.
Too much of a good thing
When servicing a washable filter, take care not to over-oil the element. Besides impeding airflow, excess oil can migrate into the intake system, where it can coat electronic sensors, which some OEMs claim may hinder the sensors' operation and result in a repair that might not be covered under warranty.
1. Step One in this procedure is the pre-clean. This is done by lightly tapping the filter to loosen any embedded dirt particles. If any dirt remains, then lightly brush with a soft-bristle brush. Then spray the filter with the cleaning solution. | 
2. Let the solution soak in for a few minutes to allow it to break down the dirt and oil on the filter. Then rinse the filter from the inside out; this removes the dirt without washing it deeper into the cotton mesh of the filter element. |
3. If there are areas that still have signs of dirt, give them another spray of cleaner. | 
4. And rinse again. Now here comes the hard part. Set the filter down and let it air-dry overnight, which should be a sufficient amount of time. Fight the urge to blow it dry with compressed air, as the pressure the air comes out is too much and will disrupt the fibers in the cotton and in turn compromise the filtering abilities of the filter. |
5. Once the filter is dry, place a few drops of oil on the top of each pleat. Then set the filter down and let the oil wick its way throughout the cotton. Once the oil has migrated over the entire filter, you can put it back on the truck. | 
6. Here is a side-by-side comparison of our now-clean filter and a new one. As you can see, our filter isn't the same color because the old oil and contaminants stained the cotton. It will still provide the same great filtering abilities, but it will be a little darker, so don't be too concerned about the coloring. |